class Car {
    int speed;
    void upSpeed(int m){
        if(m>0)
          speed += m; 
    } 
}
public class E {
    public static void main(String args[]) {
       Car carOne = new Car();
       Car carTwo = new Car();
       carOne.upSpeed(50);
       carTwo.upSpeed(100); 
       System.out.printf("%d:%d",carOne.speed,carTwo.speed); //【代码】
    }
}